trigo
posted by anjelica318 .
how do i verify these?
1sin^2B
1.  = csc^2Bsec^2B
sin^2Bcos^B
2. cos(2a+a) = 4cos^3a3cosa

1. What exponent goes between ^ and cos? If it is 2, I do not believe the identity is valid as written.
What IS valid is
1/sin^2 B  sin^2B/(sin^2B cos^2 B) =
csc^2 B  sec^2 B
or
[cos^2 B  sin^2 B]/[sin^2B cos^2B ] =
csc^2 B  sec^2 B 
1. (1sin²B)/(sin²Bcos²B)= csc²Bsec²B
that's really the given. please help.